This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this study is to observe brain glucose metabolic activity in "aggression prone" subjects compared to "non-aggression prone" subjects. Subjects will be grouped "aggression prone" or "non-aggression prone" via questionaire after watching a 3 minute sample video of R-rated scenes of violence from movies. Then they will watch a longer video of violent scenes while lying in the Positron Emission Tomography (PET) scanner.